Process for producing isocyanate-based foam construction boards

ABSTRACT

A process for producing a polyurethane or polyisocyanurate construction board, the process comprising: (i) providing an A-side reactant stream that includes an isocyanate-containing compound; (ii) providing a B-side reactant stream that includes a polyol, where the B-side reactant stream includes a blowing agent that includes a pentane and a blowing agent additive that has a Hansen Solubility Parameter (8t) that is greater than 17 MPa°′ 5 ; and (iii) mixing the A-side reactant stream with the B-side reactant stream to produce a reaction mixture.

This application is a National-Stage application of PCT/US2016/064867filed on Dec. 3, 2016, which claims the benefit of U.S. ProvisionalApplication Ser. No. 62/264,387 filed on Dec. 8, 2015; U.S. ProvisionalApplication Ser. No. 62/290,054 filed on Feb. 2, 2016; U.S. ProvisionalApplication Ser. No. 62/336,610 filed on May 14, 2016; U.S. ProvisionalApplication Ser. No. 62/336,608 filed on May 14, 2016; U.S. ProvisionalApplication Ser. No. 62/336,605 filed on May 14, 2016; and U.S.Provisional Application Ser. No. 62/340,267 filed on May 23, 2016; whichare incorporated herein by reference.

FIELD OF THE INVENTION

Embodiments of the present invention are directed toward a process forproducing isocyanate-based foam construction boards (e.g. polyurethaneand polyisocyanurate boards) having improved insulating properties. Inone or more embodiments, the construction boards are prepared byemploying a physical blowing agent that includes a pentane and a blowingagent additive that provides improved R-Value at a median temperature of40° F. relative to the R-Value at a median temperature of 75° F.

BACKGROUND OF THE INVENTION

Polyurethane and polyisocyanurate foam construction boards, which mayalso be referred to as isocyanate-based construction boards, arecommonly employed in the construction industry. For example, these foaminsulation boards are commonly employed as insulation within flat orlow-sloped roofs.

Isocyanate-based construction boards are cellular in nature andtypically include an insulating compound trapped within the closed cellsof the relatively rigid foam. Many insulating compounds have been usedover the years. For example, halogenated hydrocarbons, such astrichlorofluoromethane (CFC-11), were employed. These materials werephased out in favor of hydrochlorofluorocarbons, such as1,1-dichloro-1-fluoroethane (HCFC-141b). The hydrochlorofluorocarbonswere then replaced with hydrocarbons such as various pentane isomers.For example, it is common to produce construction boards by employingn-pentane, isopentane, and/or cyclopentane as blowing agents.

Construction boards are often characterized by one or moretechnologically important characteristics. For example, theisocyanate-based construction boards may be characterized by an ISOindex, which generally refers to the equivalents of NCO groups toisocyanate-reactive groups. Insulation and cover boards having an indexof greater than about 200 are desirable because these foam constructionboards demonstrate improved dimensional stability and better flameresistance than lower index foams.

Another technologically important characteristic is the insulatingproperty of the foam construction board. This characteristic istypically quantified based upon “R-Value.” As a skilled person willappreciate, R-Value represents the ability of a given material to resistheat transfer. This resistance can change with the temperaturedifferential being observed, as well as the median temperature. Forexample, consumer products are often designated with an R-Value measuredat a 40° F. differential and a median temperature of 75° F.; in otherwords, the insulating value is determined between environments set at55° F. and 95° F. It is often important to measure R-Value by employinga 40° F. differential at a 40° F. median temperature (i.e. betweenenvironments set at 20° F. and 60° F.). Generally speaking, due tothermodynamic phenomena, R-Value is typically higher at lower mediantemperatures.

Yet another important characteristic of construction boards isdimensional stability, which generally relates to the ability of theboard to maintain its shape and volume when subjected to temperaturechanges. In other words, dimensional stability relates to the degree towhich the boards shrink or warp. This is an important considerationbecause gaps that are formed between adjacent boards cause thermalshorting and undermine the insulating value of a roof system. As theskilled person appreciates, the dimensional stability of constructionboards can be determined by ASTM D-2126-09.

Another important characteristic of construction boards is compressivestrength, which generally relates to the force required to compromise aconstruction board. This is an important factor in several respects.First, where a construction board has inferior compressive strength, theconstruction boards do not adequately withstand forces that aresubjected to a roof surface, which can include environmental forces suchas snow and hail, as well as foot traffic that is often experienced on aroof. Additionally, construction boards having inferior compressivestrength often produce roof systems having inferior wind uplift ratings.For example, where the construction boards are secured to a roof surfaceusing mechanical fasteners, fastener pull through is inverselyproportional to compressive strength. As the skilled person appreciates,compressive strength of construction boards can be determined by ASTMD-1621-10.

Another important characteristic is the friability of the constructionboard. Where the foam body of the construction board is too friable, theusefulness of the construction board can be compromised. For example,facer adhesion to the foam body can be easily compromised where the foamis too friable. Facer delamination can have an adverse impact ondimensional stability, as well as wind uplift especially where a roofingmembrane is adhered to the facer.

It is obviously desirable to increase the insulating ability of the foamconstruction boards without drastically altering other characteristicsof the board. In particular, there is a desire to maintain theinsulating properties of construction boards over longer periods oftime.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provide a process forproducing a polyurethane or polyisocyanurate construction board, theprocess comprising (i) providing an A-side reactant stream that includesan isocyanate-containing compound; (ii) providing a B-side reactantstream that includes a polyol, where the B-side reactant stream includesa blowing agent that includes a pentane and a blowing agent additivethat has a Hansen Solubility Parameter (δt) that is greater than 17MPa^(−0.5); and (iii) mixing the A-side reactant stream with the B-sidereactant stream to produce a reaction mixture.

Yet other embodiments of the present invention provide a process forproducing a polyurethane or polyisocyanurate construction board, theprocess comprising (i) combining polyol, isocyanate, an acyclic pentaneblowing agent, a blowing agent additive that has a Hansen SolubilityParameter (δt) that is greater than 17 MPa^(−0.5), and less than 1.5parts by weight water per 100 parts by weight polyol to form afoam-forming mixture where the ratio of polyol to isocyanate provides aclosed-cell foam having an Index of at least 210, and where the amountof acyclic pentane, blowing agent additive, and any water presentprovide a closed-cell foam having a density of 1.0 to 2.5 lbs/ft³, andwhere the acyclic pentane and blowing agent additive form a blowingagent mixture, and where the blowing agent mixture includes from about 7to about 35 mole % blowing agent additive based on the total moles ofblowing agent mixture; (ii) depositing the foam-forming mixture on afacer; and (iii) heating the foam-forming mixture to form a closed-cellfoam.

Still other embodiments of the present invention provide a method ofimproving the R-Value of a construction board at a median temperature of40° F. relative to the R-Value of the construction board at a mediantemperature of 75° F., the method comprising of preparing apolyisocyanurate construction board by forming a foam-forming mixture bycombining an isocyanate, an aromatic polyester polyol, less than 1.5parts by weight water per 100 parts by weight polyol, and a physicalblowing agent including an acyclic pentane and a blowing agent additivethat has a Hansen Solubility Parameter (δt) that is greater than 17MPa^(−0.5), where the physical blowing agent mixture includes from about7 to about 30 mole % of the blowing agent additive based on the totalmoles of the physical blowing agent mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

The FIGURE is a flow chart showing a process of one or more embodimentsof the invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the present invention are based, at least in part, on thediscovery of a process for producing isocyanate-based constructionboards that employs a pentane blowing agent and a blowing agent additivethat has a Hansen Solubility Parameter (δ_(t)) that is greater than 17.0MPa^(−0.5). In particular embodiments, the pentane and the blowing agentadditive are included in the isocyanate-reactive stream of reactants(which is often referred to as the B-side stream), which is combinedwith the isocyanate compounds during formation of the foam. A problemthat has been observed is that relatively high index foam constructionboards that are prepared by employing aromatic polyester polyols andpentane blowing agents have an R-Value at a 40° F. median temperaturethat is lower than the R-Value at a 75° F. median temperature. In theface of this problem, it has unexpectedly been found that by includingthe blowing agent additives defined herein together with the pentaneblowing agent, the insulating properties of the resultant constructionboards can be increased at lower median temperatures (e.g. 40° F.). Infact, it has unexpectedly been found that practice of the presentinvention provides construction boards with an R-value at a 40° F.median temperature that is markedly greater than the R-value at a 75° F.median temperature. Still further, the unexpected results observedrelative to R-value were especially surprising when viewed incombination with the advantageous balance of properties that have beenobserved when construction boards are prepared according to the presentinvention.

Process Overview

As suggested above, practice of the present invention includes preparingan isocyanate-based foam by employing a pentane blowing agent, inparticular embodiments an acyclic pentane, and a blowing agent additiveas the physical blowing agents. As a skilled person appreciates, theproduction of foam may include the use of physical blowing agents aswell as chemical blowing agents. Typical chemical blowing agents includewater as will be described in greater detail below. Unless otherwisespecified, for purposes of this specification, reference to the termblowing agents or blowing agent mixture refers to the physical blowingagents, which as suggested above includes the pentane and the blowingagent additive.

As used herein, the term isocyanate-based foam may include polyurethaneand polyisocyanurate foams, and terms foam, polyurethane andpolyisocyanate may be generally used interchangeably unless specificallyindicated. For example, where a technical distinction must be madebetween polyurethane and polyisocyanurate foam, the ISO index will beused to make any required technical distinctions.

In one or more embodiments, the foam is prepared by mixing a firststream that includes an isocyanate-containing compound with a secondstream that includes an isocyanate-reactive compound. Using conventionalterminology, the first stream (i.e., the stream including anisocyanate-containing compound) may be referred to as an A-side stream,an A-side reactant stream, or simply an A stream. Likewise, the secondstream (i.e., the stream including an isocyanate-reactive compound) maybe referred to as a B-side stream, B-side reactant stream, or simply Bstream. In one or more embodiments, either stream may carry additionalingredients including, but not limited to, flame-retardants,surfactants, blowing agents, catalysts, emulsifiers/solubilizers,fillers, fungicides, anti-static substances, and mixtures of two or morethereof.

In one or more embodiments, the acyclic pentane blowing agent and ablowing agent additive in accordance with practice of this invention areincluded within the B-side stream of reactants. In alternateembodiments, the acyclic pentane blowing agent and a blowing agentadditive in accordance with practice of this invention are includedwithin the A-side stream of reactants. In yet other embodiments, theacyclic pentane blowing agent and a blowing agent additive in accordancewith practice of this invention are included within both the A-side andB-side stream of reactants.

A-Side Stream

In one or more embodiments, the A-side stream may only contain theisocyanate-containing compound. In one or more embodiments, multipleisocyanate-containing compounds may be included in the A-side. In otherembodiments, the A-side stream may also contain other constituents suchas, but not limited to, flame-retardants, surfactants, blowing agentsand other non-isocyanate-reactive components. In one or moreembodiments, the complementary constituents added to the A-side arenon-isocyanate reactive. And, as suggested above, the A-side may includethe acyclic pentane blowing agent and the blowing agent additive inaccordance with the present invention. In other embodiments, the A-sideis devoid or substantially devoid of the acyclic blowing agent and theblowing agent additive.

Suitable isocyanate-containing compounds useful for the manufacture ofpolyisocyanurate construction board are generally known in the art andembodiments of this invention are not limited by the selection of anyparticular isocyanate-containing compound. Useful isocyanate-containingcompounds include polyisocyanates. Useful polyisocyanates includearomatic polyisocyanates such as diphenyl methane diisocyanate in theform of its 2,4′-, 2,2′-, and 4,4′-isomers and mixtures thereof. Themixtures of diphenyl methane diisocyanates (MDI) and oligomers thereofmay be referred to as “crude” or polymeric MDI, and thesepolyisocyanates may have an isocyanate functionality of greater than 2.Other examples include toluene diisocyanate in the form of its 2,4′ and2,6′-isomers and mixtures thereof, 1,5-naphthalene diisocyanate, and1,4′ diisocyanatobenzene. Exemplary polyisocyanate compounds includepolymeric Rubinate 1850 (Huntsmen Polyurethanes), polymeric LupranateM70R (BASF), and polymeric Mondur 489N (Bayer).

B-Side Stream

In one or more embodiments, the B-side stream may only include theisocyanate-reactive compound. In one or more embodiments, multipleisocyanate-reactive compounds may be included in the B-side. In otherembodiments, the B-side stream may also contain other constituents suchas, but not limited to, water, flame-retardants, surfactants, blowingagents and other non-isocyanate-containing components. In particularembodiments, the B-side includes an isocyanate reactive compound, theacyclic pentane blowing agent, and the blowing agent additive. In theseor other embodiments, the B-side may also include flame retardants,catalysts, emulsifiers/solubilizers, surfactants, fillers, fungicides,anti-static substances, and other ingredients that are conventional inthe art.

An exemplary isocyanate-reactive compound is a polyol. The term polyol,or polyol compound, includes diols, polyols, and glycols, which maycontain water as generally known in the art. Primary and secondaryamines are suitable, as are polyether polyols and polyester polyols. Inparticular embodiments, aromatic polyester polyols are employed.Exemplary polyester polyols include phthalic anhydride based PS-2352(Stepan), phthalic anhydride based polyol PS-2412 (Stepan), teraphthalicbased polyol 3522 (Invista), and a blended polyol TR 564 (Huntsman).Useful polyether polyols include those based on sucrose, glycerin, andtoluene diamine. Examples of glycols include diethylene glycol,dipropylene glycol, and ethylene glycol. Suitable primary and secondaryamines include, without limitation, ethylene diamine, anddiethanolamine. In one or more embodiments, a polyester polyol isemployed. In one or more embodiments, the present invention may bepracticed in the appreciable absence of any polyether polyol. In certainembodiments, the ingredients are devoid of polyether polyols.

Catalysts

Catalysts, which are believed to initiate the polymerization reactionbetween the isocyanate and the polyol, as well as a trimerizationreaction between free isocyanate groups when polyisocyanurate foam isdesired, may be employed. While some catalysts expedite both reactions,two or more catalysts may be employed to achieve both reactions. Usefulcatalysts include salts of alkali metals and carboxylic acids orphenols, such as, for example potassium octoate; mononuclear orpolynuclear Mannich bases of condensable phenols, oxo-compounds, andsecondary amines, which are optionally substituted with alkyl groups,aryl groups, or aralkyl groups; tertiary amines, such aspentamethyldiethylene triamine (PMDETA), 2,4,6-tris[(dimethylamino)methyl]phenol, triethyl amine, tributyl amine, N-methylmorpholine, and N-ethyl morpholine; basic nitrogen compounds, such astetra alkyl ammonium hydroxides, alkali metal hydroxides, alkali metalphenolates, and alkali metal acholates; and organic metal compounds,such as tin(II)-salts of carboxylic acids, tin(IV)-compounds, and organolead compounds, such as lead naphthenate and lead octoate.

Surfactants, Emulsifiers and Solubilizers

Surfactants, emulsifiers, and/or solubilizers may also be employed inthe production of polyurethane and polyisocyanurate foams in order toincrease the compatibility of the blowing agents with the isocyanate andpolyol components. Surfactants may serve two purposes. First, they mayhelp to emulsify/solubilize all the components so that they reactcompletely. Second, they may promote cell nucleation and cellstabilization.

Exemplary surfactants include silicone co-polymers or organic polymersbonded to a silicone polymer. Although surfactants can serve bothfunctions, it may also be useful to ensure emulsification/solubilizationby using enough emulsifiers/solubilizers to maintainemulsification/solubilization and a minimal amount of the surfactant toobtain good cell nucleation and cell stabilization. Examples ofsurfactants include Pelron surfactant 9920, Evonik B8489, and GE 6912.U.S. Pat. Nos. 5,686,499 and 5,837,742 are incorporated herein byreference to show various useful surfactants.

Suitable emulsifiers/solubilizers include DABCO Ketene 20AS (AirProducts), and Tergitol NP-9 (nonylphenol+9 moles ethylene oxide).

Flame Retardants

Flame Retardants may be used in the production of polyurethane andpolyisocyanurate foams, especially when the foams contain flammableblowing agents such as pentane isomers. Useful flame retardants includetri(monochloropropyl) phosphate (a.k.a. tris(cloro-propyl) phosphate),tri-2-chloroethyl phosphate (a.k.a tris(chloro-ethyl) phosphate),phosphonic acid, methyl ester, dimethyl ester, and diethyl ester. U.S.Pat. No. 5,182,309 is incorporated herein by reference to show usefulblowing agents.

Pentane Blowing Agents

In one or more embodiments, the blowing agent includes one or morepentane isomers selected from n-pentane, isopentane, cyclopentane andmixtures thereof. In particular embodiments, the pentane blowing agentis an acyclic pentane such as isopentane, n-pentane, or mixturesthereof. In some embodiments, the acyclic pentane is a blend ofn-pentane and isopentane. In this respect, U.S. Pat. Nos. 7,612,120,7,838,568, 8,106,106 and 8,453,390 are incorporated herein by reference.

Blowing Agent Additive

In one or more embodiments, the blowing agent additive is an organiccompound having a Hansen Solubility Parameter (δ_(t)) that is greaterthan 17.0, in other embodiments greater than 17.5, in other embodimentsgreater than 18.0, in other embodiments greater than 18.5, in otherembodiments greater than 19.0, and in other embodiments greater than19.5 MPa^(−0.5) at 25° C. In these or other embodiments, the blowingagent additive is an organic compound having a Hansen SolubilityParameter (δ_(t)) of from about 17.0 to about 35.0, in other embodimentsfrom about 17.5 to about 33.0, in other embodiments from about 18.0 toabout 30.0, in other embodiments from about 18.5 to about 28.0, and inother embodiments from about 19.0 to about 26.0 MPa^(−0.5) at 25° C.

As the skilled person appreciates, the Hansen Solubility Parameter isbased upon empirical evidence relating to the energy from dispersionforces between molecules (δ_(d)), energy from dipolar intermolecularforces between molecules (δ_(p)), and energy from hydrogen bonds betweenmolecules (δ_(h)). These components contribute to a Hansen TotalCohesion Parameter (δ_(t)). Unless otherwise stated, reference to HansenSolubility Parameter (δ_(t)) will refer to the Hansen Total CohesionParameter. Further explanation and the Hansen Solubility Parameters(δ_(t)) of many common organic molecules are provided in the HANDBOOK OFSOLUBILITY PARAMETERS AND OTHER COHESION PARAMETERS, CRC Press, Pages76-121, which is incorporated herein by reference.

In one or more embodiments, the blowing agent additive is alsocharacterized by a boiling point, at one atmosphere, of less than 150°C., in other embodiments less than 130° C., in other embodiments lessthan 115° C., in other embodiments less than 100° C., in otherembodiments less than 90° C., and in other embodiments less than 80° C.In these or other embodiments, the blowing agent additive is alsocharacterized by a boiling point, at one atmosphere, that is greaterthan 5° C., in other embodiments greater than 10° C., in otherembodiments greater than 12° C., in other embodiments greater than 15°C., and in other embodiments greater than 18° C. In one or moreembodiments, the blowing agent additive is characterized by a boilingpoint, at one atmosphere, of from about 5° C. to 150° C., in otherembodiments from about 10° C. to 130° C., in other embodiments fromabout 12° C. to 115° C., in other embodiments from about 15° C. to 100°C., and in other embodiments from about 18° C. to 90° C.

In one or more embodiments, the blowing agent additive may be selectedfrom ketones, aldehydes, ethers, esters, halogenated hydrocarbons, andaromatics. In one or more embodiments, the blowing agent additive is alow molecular weight additive. In one or more embodiments, the blowingagent additive is characterized by a molecular weight of less than 150g/mole, in other embodiments less than 140 g/mole, in other embodimentsless than 130 g/mole, in other embodiments less than 120 g/mole, inother embodiments less than 100 g/mole, in other embodiments less than90 g/mole, in other embodiments less than 80 g/mole, and in otherembodiments less than 70 g/mole.

Ketones and Aldehydes

In one or more embodiments, the low molecular weight aldehydes orketones may be defined by one of the following formulae R(CO)R orR(CO)H, where R and R′ are independently a monovalent organic group orwhere R and R′ join to form a divalent organic group.

In one or more embodiments, the monovalent organic groups may behydrocarbyl groups or substituted hydrocarbyl groups such as, but notlimited to, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, allyl,aralkyl, alkaryl, or alkynyl groups. Substituted hydrocarbyl groupsinclude hydrocarbyl groups in which one or more hydrogen atoms have beenreplaced by a substituent such as a hydrocarbyl group. In one or moreembodiments, these groups may also contain heteroatoms such as, but notlimited to, nitrogen, boron, oxygen, silicon, sulfur, tin, andphosphorus atoms. In particular embodiments, at least one R group is anether group, which thereby forms a diether compound.

In one or more embodiments, the divalent organic groups may includehydrocarbylene groups or substituted hydrocarbylene groups such as, butnot limited to, alkylene, cycloalkylene, alkenylene, cycloalkenylene,alkynylene, cycloalkynylene, or arylene groups. Substitutedhydrocarbylene groups include hydrocarbylene groups in which one or morehydrogen atoms have been replaced by a substituent such as an alkylgroup. These groups may also contain one or more heteroatoms such as,but not limited to, nitrogen, oxygen, boron, silicon, sulfur, tin, andphosphorus atoms.

In one or more embodiments, the monovalent organic groups include one toabout 12 carbon atoms, in other embodiments from about one to about 6carbon atoms, in other embodiments from about one to about 3 carbonatoms, and in other embodiments from about one to about 2 carbon atoms.In other embodiments, the divalent organic groups include from one toabout 12 carbon atoms, in other embodiments from about 2 to about 8carbon atoms, and in other embodiments from about 3 to about 5 carbonatoms.

Useful ketones include, but are not limited to, acetone, acetophenone,butanone, cyclopentanone, ethyl isopropyl ketone, 2-hexanone,isophorone, mesityl oxide, methyl isobutyl ketone, methyl isopropylketone, 3-methyl-2-pentanone, 2-pentanone, 3-pentanone, and methyl ethylketone.

Useful aldehydes include, but are not limited to, formaldehyde,acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde,cinnamaldehyde, glyoxal, malondialdehyde, and succindialdehyde.

Esters

In one or more embodiments, the ester may be defined by R(CO)OR′, whereR is hydrogen or a monovalent organic group and R′ is a monovalentorganic group, or where R and R′ join to form a divalent organic group.The monovalent and divalent organic groups are defined above togetherwith their respective size, which definition is applicable for thisembodiment.

Useful esters include, but are not limited to, methyl formate, ethylformate, n-propyl formate, isopropyl formate, n-butyl formate, isobutylformate, t-butyl formate, methyl acetate, ethyl acetate, n-propylacetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, t-butylacetate, methyl propanoate, ethyl propanoate, n-propyl propanoate,isopropyl propanoate, n-butyl propanoate, isobutyl propanoate, t-butylpropanoate, methyl butanoate, ethyl butanoate, n-propyl butanoate,isopropyl butanoate, n-butyl butanoate, isobutyl butanoate, and t-butylbutanoate.

Aromatic Hydrocarbon

In one or more embodiments, useful aromatic hydrocarbons include areneand heteroarene compounds. In one or more embodiments, these compoundsincludes less than 20 carbon atoms, in other embodiments less than 12carbon atoms, and in other embodiments less than 8 carbon atoms.

Useful arenes include, but are not limited to, benzene, toluene,ethylbenzene, p-1,2-dimethylbenzene, 1,4-dimethylbenzene,1,4-dimethylbenzene, mesitylene, durene, 2-phenylhexane, biphenyl,phenol, aniline, nitrobenzene, and naphthalene. Useful heteroarenesinclude, but are not limited to, azepine, oxepine, theipine, pyridine,pyran, and thiopyran.

Halogenated Hydrocarbons

In one or more embodiments, the halogenated hydrocarbon may be definedby the general formula RX_(y) where R is a monovalent organic group,each X is independently a halogen atom, and y is the number of halogenatoms within the molecule. In one or more embodiments, X is selectedfrom chlorine and fluorine atoms. In one or more embodiments, y is 1 toabout 5, in other embodiments y is 2 to 4, and in other embodiments y is2 to 3. The monovalent and divalent organic groups are defined abovetogether with their respective size, which definition is applicable forthis embodiment.

In one or more embodiments, the halogenated hydrocarbon is a halogenatedmethane, also referred to as a halomethane. In other embodiments, thehalogenated hydrocarbon is a halogenated ethane (haloethane), and inother embodiments a halogenated propane (halopropane). In yet otherembodiments, the halogenated hydrocarbon is a halogenated olefin(haloolefin).

Examples of useful halomethanes include chlorinated methanes such as,but not limited to, chloroform, methyl chloride, 1,2-dicholorethane, anddichloromethane.

Ethers

In one or more embodiments, the ethers may be defined by the formulaR—O—R, where each R is independently a monovalent organic group or eachR join to form a divalent organic group. The monovalent and divalentorganic groups are defined above together with their respective size,which definition is applicable for this embodiment.

Useful ethers include dihydrocarbyl ether, diethers, and cyclic ethers.Examples of useful dihydrocarbyl ethers include, but are not limited to,diethyl ether, dimethylether, diisopropyl ether, diisobutyl ether,di-n-propyl ether, di-isoamyl ether, di-n-butyl ether, and di-n-hexyleither. Examples of useful cyclic ethers include, but are not limitedto, ethylene oxide, tetrahydrofuran (THF), tetrahydropyran, furan, anddihydropyran. Examples of useful diethers include, but are not limitedto, dimethoxymethane, dimethoxyethane, dimethoxypropane,dimethoxyisopropane, diethoxymethane, diethoxyethane, diethoxypropane,diethoxyisopropane, dipropoxymethane, dipropoxyethane, dipropoxypropane,dipropoxyisopropane, and diethylene glycol dimethyl ether.

Amount of Reactants/Ingredients

An isocyanurate is a trimeric reaction product of three isocyanatesforming a six-membered ring. The ratio of the equivalents of NCO groups(provided by the isocyanate-containing compound or A-side) toisocyanate-reactive groups (provided by the isocyanate-containingcompound or B side) may be referred to as the index or ISO index. Whenthe NCO equivalents to the isocyanate-reactive group equivalents isequal, then the index is 1.00, which is referred to as an index of 100,and the mixture is said to be stoiciometrically equal. As the ratio ofNCO equivalents to isocyanate-reactive groups equivalents increases, theindex increases. Above an index of about 150, the material is generallyknown as a polyisocyanurate foam, even though there are still manypolyurethane linkages that may not be trimerized. When the index isbelow about 150, the foam is generally known as a polyurethane foam eventhough there may be some isocyanurate linkages. For purposes of thisspecification, reference to polyisocyanurate and polyurethane will beused interchangeably unless a specific ISO index is referenced.

In one or more embodiments, the concentration of theisocyanate-containing compound to the isocyanate-reactive compoundswithin the respective A-side and B-side streams is adjusted to providethe foam product with an ISO index of at least 150, in other embodimentsat least 170, in other embodiments at least 190, in other embodiments atleast 210, in other embodiments at least 220, in other embodiments atleast 225, in other embodiments at least 230, in other embodiments atleast 235, in other embodiments at least 240, in other embodiments atleast 245, and in other embodiments at least 250. In these or otherembodiments, the concentration of the isocyanate-containing compound tothe isocyanate-reactive compounds within the respective A-side andB-side streams is adjusted to provide the foam product with an ISO indexof at most 400, in other embodiments at most 350, and in otherembodiments at most 300. In one or more embodiments, the concentrationof the isocyanate-containing compound to the isocyanate-reactivecompounds within the respective A-side and B-side streams is adjusted toprovide the foam product with an ISO index of from about 150 to about400, in other embodiments from about 170 to about 350, and in otherembodiments from about 190 to about 330, and in other embodiments fromabout 220 to about 280.

In one or more embodiments, the amount of physical blowing agent (i.e.,acyclic pentane and blowing agent additive) used in the manufacture ofpolyisocyanurate foam construction board according to the presentinvention may be described with reference to the amount ofisocyanate-reactive compound employed (e.g. polyol). For example, in oneor more embodiments, at least 12, in other embodiments at least 14, andin other embodiments at least 18 parts by weight physical blowing agentper 100 parts by weight of polyol may be used. In these or otherembodiments, at most 40, in other embodiments at most 36, and in otherembodiments at most 33 parts by weight physical blowing agent per 100parts by weight of polyol may be used. In one or more embodiments, fromabout 12 to about 40, in other embodiments from about 14 to about 36,and in other embodiments from about 18 to about 33 of physical blowingagent per 100 parts by weight of polyol may be used.

In one or more embodiments, the amount of physical blowing agent (i.e.,acyclic pentane and blowing agent additive), optionally together withany chemical blowing agent employed, used in the manufacture ofpolyisocyanurate foam construction board according to the presentinvention may be described with reference to the density of theresulting foam. In other words, the skilled person appreciates that theamount of blowing agent employed has a direct impact on the density ofthe foam produced, and these amounts can be determined without unduecalculation or experimentation. Accordingly, in one or more embodiments,the amount of blowing agent employed (both physical and chemical blowingagent) is tailored to produce a foam having a density (as determined byASTM C303-10) of from about 1.0 to about 2.5 lbs/ft³, in otherembodiments from about 1.2 to about 2.2 lbs/ft³, in other embodimentsfrom about 1.4 to about 2.0 lbs/ft³, and in other embodiments from about1.5 to about 1.8 lbs/ft³. In particular embodiments, the amount ofblowing agent employed is tailored to produce a foam having a density ofless than 2.5 lbs/ft³, in other embodiments less than 2.2 lbs/ft³, inother embodiments less than 2.0 lbs/ft³, and in other embodiments lessthan 1.8 lbs/ft³.

In one or more embodiments, the amount of the blowing agent additive maybe described as a percentage of the amount of physical blowing agentemployed (in other words, the amount of blowing agent additive relativeto the acyclic pentane and the blowing agent additive combined). Thus,in one or more embodiments, the amount of blowing agent additiveincluded within the foam-forming ingredients is greater than 5 wt %, inother embodiments greater than 10 wt %, and in other embodiments greaterthan 12 wt % based upon the entire weight of the physical blowing agent.In these or other embodiments, the amount of blowing agent additive isless than 50 wt %, in other embodiments less than 25 wt %, and in otherembodiments less than 20 wt % based upon the entire weight of thephysical blowing agent, is included within the foam-forming ingredients.In one or more embodiments, from about 5 to about 50 wt %, in otherembodiments from about 10 to about 25 wt %, and in other embodimentsfrom about 12 to about 20 wt % blowing agent additive, based upon theentire weight of the physical blowing agent, is included within thefoam-forming ingredients. It should be understood that these amounts canlikewise be employed even where the blowing agent additive areintroduced directly to the mixhead, as will be explained in greaterdetail below.

Since the molecular weight of the various blowing agent additives mayvary, it is also useful to describe the amount of blowing agent additiveemployed in the present invention as a mole percentage of the amount ofphysical blowing agent. In one or more embodiments, the amount ofblowing agent additive included within the foam-forming ingredients isgreater than 5 mole %, in other embodiments greater than 10 mole %, andin other embodiments greater than 12 mole % based upon the entire molesof the physical blowing agent. In these or other embodiments, the amountof blowing agent additive is less than 50 mole %, in other embodimentsless than 25 mole %, and in other embodiments less than 20 mole % basedupon the entire moles of the physical blowing agent, is included withinthe foam-forming ingredients. In one or more embodiments, from about 5to about 50 mole %, in other embodiments from about 7 to about 35 mole%, in other embodiments from about 10 to about 30 mole %, and in otherembodiments from about 12 to about 27 mole % blowing agent additive,based upon the entire moles of the physical blowing agent, is includedwithin the foam-forming ingredients.

In one or more embodiments, the amount of the blowing agent additive maybe described as a function of the weight of the polyol. Thus, in one ormore embodiments, the amount of blowing agent additive included withinthe foam-forming ingredients is greater than 0.9 parts by weight, inother embodiments greater than 2.0 parts by weight, and in otherembodiments greater than 3.3 parts by weight per 100 parts by weightpolyol. In these or other embodiments, the amount of blowing agentadditive is less than 10.0, in other embodiments less than 6.0, and inother embodiments less than 5.0 parts by weight blowing agent additiveper 100 parts by weight polyol. In one or more embodiments from about0.9 to about 10.0, in other embodiments from about 2.0 to about 6.0, andin other embodiments from about 3.3 to about 5.0 parts by weight blowingagent additive per 100 parts by weight polyol is included within thefoam-forming ingredients.

In one or more embodiments, the amount of the blowing agent additive maybe described in terms of a molar ratio of blowing agent additive toacyclic pentane, which is defined in terms of the moles of blowing agentadditive to moles of acyclic pentane. Thus, in one or more embodiments,the molar ratio of blowing agent additive to acyclic pentane is greaterthan 1:20, in other embodiments greater than 1:10, and in otherembodiments greater than 1:4. In these or other embodiments, the molarratio of blowing agent additive to acyclic pentane is less than 1:1, inother embodiments less than 1:1.5, and in other embodiments less than1:2. In one or more embodiments, the molar ratio of blowing agentadditive to acyclic pentane is from about 1:20 to about 1:1, in otherembodiments from about 1:10 to about 1:1.5, and in other embodimentsfrom about 1:4 to about 2:1. It should be understood that these amountscan likewise be employed even where the blowing agent additive areintroduced directly to the mixhead, as will be explained in greaterdetail below.

In one or more embodiments, the amount of the blowing agent additive maybe described as a function of the weight of the polyol. Thus, in one ormore embodiments, the amount of blowing agent additive included withinthe foam-forming ingredients is greater than 0.9, in other embodimentsgreater than 2.0, and in other embodiments greater than 3.3 moles ofblowing agent additive per 100 grams of polyol. In these or otherembodiments, the amount of blowing agent additive is less than 10.0, inother embodiments less than 6.0, and in other embodiments less than 5.0moles of blowing agent additive per 100 grams of polyol. In one or moreembodiments from about 0.9 to about 10.0, in other embodiments fromabout 2.0 to about 6.0, and in other embodiments from about 3.3 to about5.0 moles of blowing agent additive per 100 grams of polyol is includedwithin the foam-forming ingredients.

In one or more embodiments, the physical blowing agent is devoid orsubstantially devoid of cyclopentane, where substantially devoid refersto that amount or less of cyclopentane that does not have an appreciableimpact on the practice of the invention and/or the advantageousproperties observed in the construction boards of this invention. In oneor more embodiments, the blowing agent employed in practicing thepresent invention includes less than 10 mole percent, in otherembodiments less than 5 mole percent, and in other embodiments less than1 mole percent cyclopentane based upon the entire blowing agent mixture,which refers to the physical blowing agents (i.e. the acyclic pentaneand the blowing agent additive).

In one or more embodiments, the amount of surfactant (e.g., siliconecopolymer) used in the manufacture of polyisocyanurate foam constructionboard according to the present invention may be described with referenceto the amount of isocyanate-reactive compound employed (e.g. polyol).For example, in one or more embodiments, at least 1.0, in otherembodiments at least 1.5, and in other embodiments at least 2.0 parts byweight surfactant per 100 parts by weight of polyol may be used. Inthese or other embodiments, at most 5.0, in other embodiments at most4.0, and in other embodiments at most 3.0 parts by weight surfactant per100 parts by weight of polyol may be used. In one or more embodiments,from about 1.0 to about 5.0, in other embodiments from about 1.5 toabout 4.0, and in other embodiments from about 2.0 to about 3.0 ofsurfactant per 100 parts by weight of polyol may be used.

In one or more embodiments, the amount of flame retardant (e.g., liquidphosphates) used in the manufacture of polyisocyanurate foamconstruction board according to the present invention may be describedwith reference to the amount of isocyanate-reactive compound employed(e.g. polyol). For example, in one or more embodiments, at least 5, inother embodiments at least 10, and in other embodiments at least 12parts by weight flame retardant per 100 parts by weight of polyol may beused. In these or other embodiments, at most 30, in other embodiments atmost 25, and in other embodiments at most 20 parts by weight flameretardant per 100 parts by weight of polyol may be used. In one or moreembodiments, from about 5 to about 30, in other embodiments from about10 to about 25, and in other embodiments from about 12 to about 20 offlame retardant per 100 parts by weight of polyol may be used.

In one or more embodiments, the amount of catalyst (s) employed inpractice of the present invention can be readily determined by theskilled person without undue experimentation or calculation. Indeed, theskilled person is aware of the various process parameters that willimpact the amount of desired catalyst.

In one or more embodiments, the amount of physical blowing agent (i.e.pentane together with the amount of blowing agent additives) that isemployed is sufficient to provide a foam having a foam density (ASTMC303-10) that is less than 2.5 pounds per cubic foot (12 kg/m2), inother embodiments less than 2.0 pounds per cubic foot (9.8 kg/m2), inother embodiments less than 1.9 pounds per cubic foot (9.3 kg/m2), andstill in other embodiments less than 1.8 pounds per cubic foot (8.8kg/m2). In one or more embodiments, the amount of blowing agent(together with the amount of blowing agent additives) that is employedis sufficient to provide a density that is greater than 1.50 pounds percubic foot (7.32 kg/m2), or in other embodiments, greater than 1.55pounds per cubic foot (7.57 kg/m2).

Chemical Blowing Agents

As suggested above, the construction boards of the present invention maybe produced in the presence of a chemical blowing agent in addition tothe physical blowing agents described above. The presence of excessiveamounts of chemical blowing agents, such as water, has a deleteriousimpact on the overall balance of properties of the construction boardsof the present invention. Accordingly, in one or more embodiments, theamount of chemical blowing agent employed in the manufacture of theconstruction boards of this invention, such as water, is limited.Accordingly, the amount of chemical blowing agent (e.g., water) includedwithin the foam-forming ingredients according to the present invention,particularly the B-side stream of reactants) is less than 1.5, in otherembodiments less than 1.3, in other embodiments less than 1.0, in otherembodiments less than 0.8, in other embodiments less than 0.6, and inother embodiments less than 0.4 parts by weight chemical blowing agent(e.g., water) per 100 parts by weight of the isocyanate-reactivecomponent (e.g., 100 parts by weight polyol, php).

The skilled person understands that the ingredients employed in themanufacture of polyurethane-polyisocyanurate foams in accordance withthe present invention employs ingredients that inherently include water.Thus, unless efforts are made to remove water from the ingredients,certain levels of water are inherently introduced to the reactionmixture. It is conventionally believed that the amount of waterinherently present within the reactants is about 0.15 to about 0.2 partsby weight water per 100 parts by weight polyol (php). Accordingly, thetotal amount of chemical blowing agent within the foam forming mixtureincludes the amount of inherent water within the reactants plus anyadded chemical blowing agent, such as added water. In one or moreembodiments, chemical blowing agent, particularly water, may be added tothe foam-forming ingredients while staying within the maximum amountsset forth above. For example, in one or more embodiments, from about 0.1to about 0.8, in other embodiments from about 0.2 to about 0.7, and inother embodiments from about 0.25 to about 0.6 parts by weight water per100 parts by weight polyol (php) may be added to the foam formingingredients. In particular embodiments, the chemical blowing agent isadded to the B-side stream of reactants.

Method of Making

An overview of a process according to embodiments of the presentinvention can be described with reference to the FIGURE. The process 10includes providing an A-side stream of reactants 12 and a B-side streamof reactants 14. As described above, the A-side stream of reactantsincludes an isocyanate-containing compounds and the B-side stream ofreactants includes an isocyanate-reactive compound. A-side 12 and B-side14 may be combined at mixhead 16.

In accordance with the present invention, a blowing agent additive 15 isincluded within the B-side stream. Also, in optional embodiments, athreshold amount of water 17 is included in the B-side. The order inwhich the ingredients are added in forming the B-side stream can bevaried. And, the timing of the addition of the blowing agent additivecan be varied. For example, in one or more embodiments, blowing agentadditive is combined with the polyol 16 within a batch mixer togetherwith one or more of the other ingredients except for the blowing agent.Once this initial mixture is prepared, blowing agent 21 can be added tothe mixture to form the B-side stream. The skilled person will readilyappreciate other orders of addition that can be employed. In otherembodiments, blowing agent additive 15 can be introduced directly tomixhead 16, where it is simultaneously introduced to the A-side andB-side stream of reactants.

In one or more embodiments, the blowing agent additive (and optionallythe threshold amount of water) is preblended with one or moreconstituents of the foam foaming ingredients. For example, the lowmolecular weight ester may be preblended with the hydrocarbon blowingagent (e.g., acyclic pentane) and the blend of the hydrocarbon andblowing agent additive is then introduced into the process for forming afoam as described herein.

In one or more embodiments, a blowing agent additive is introduced tothe B-side stream of reactants by using an in-line continuous mixer at apressure of less than 3,400 kPa, wherein the blowing agent additive andthe polyol component are continuously charged in separate streamsadvanced at predetermined flow rates chosen to bring about a desiredratio of blowing agent additive to polyol component within the in-linemixer. In one or more embodiments, the blowing agent additive and thepolyol are mixed at pressure of a less than 3,400 kPa to dissolve oremulsify the polyol and blowing agent additive within the B-side stream.Methods by which the blowing agent additive may be introduced to theB-side stream include those methods for introducing other constituentsto the B-side stream, and in this regard, U.S. Publ. No. 2004/0082676 isincorporated herein by reference.

In one or more embodiments, a blowing agent additive is introduced tothe B-side stream (i.e. combined with the polyol) prior to introducingthe blowing agent to the B-side stream. In these or other embodiments, ablowing agent additive is introduced to the B-side stream (i.e. combinedwith the polyol) after introducing the blowing agent to the B-sidestream. In these or embodiments, a blowing agent additive is introducedto the B-side stream (i.e. combined with the polyol) simultaneously withthe blowing agent. As suggested above, in alternate embodiments, whichare also shown in the FIGURE, the blowing agent additive can be includedin the A-side, either exclusively or in combination with addition to theB-side or in addition to inclusion at the mixhead.

The respective streams (12, 14) are mixed within, for example, a mixhead16 to produce a reaction mixture. Embodiments of the present inventionare not limited by the type of mixing or device employed to mix theA-side stream and the B-side stream. In one or more embodiments, theA-side stream of reactants and the B-side stream of reactants may bemixed within an impingement mixhead. In particular embodiments, mixingtakes place at a temperature of from about 5 to about 45° C. In these orother embodiments, mixing takes place at a pressure in excess of 1,000,in other embodiments in excess of 1.5, and in other embodiments inexcess of 2,000 psi.

The mixture can then be deposited onto a facer that is positioned withinand carried by a laminator 18. While in laminator 18, the reactionmixture rises and can be married to a second facer to form a composite,which may also be referred to as a laminate, wherein the foam issandwiched between upper and lower facers. The composite, while inlaminator 18, or after removal from laminator 18, is exposed to heatthat may be supplied by, for example, oven 20. For example, laminator 18may include an oven or hot air source that heats the slats and sideplates of the laminator and there through transfers heat to the laminate(i.e. to the reaction mixture).

Once subjected to this heat, the composite (i.e. the reaction mixture),or a portion of the composite (i.e. reaction mixture) can undergoconventional finishing within a finishing station 24, which may include,but is not limited to, trimming and cutting.

Method of Improving R-Value

It should therefore be appreciated that practice of the presentinvention provides a method for improving the R-Value of rigid,closed-cell polyisocyanurate construction boards, particularly thoseprepared with aromatic polyester polyols and a pentane blowing agent.The method, which is described herein, includes, at least in part, theinclusion of appropriate amounts of blowing agent additive into thefoam-forming mixture. In particular, this improvement in R-Value is atlower temperatures relative to the R-Value at higher temperatures.Specifically, the present invention provides a method for improving theR-Value of construction boards at a low median temperature (e.g., 40°F.) relative to the R-Value at a higher median temperature (e.g., 75°F.). In one or more embodiments, the methods of these embodimentsimprove the R-Value of construction boards at a median temperature of40° F. relative to the R-Value at a median temperature of 75° F. by atleast 1%, in other embodiments by at least 2%, in other embodiments byat least 3%, in other embodiments by at least 4%, in other embodimentsby at least 5%, and in other embodiments by at least 6%. In one or moreembodiments, the construction boards that are improved according tothese embodiments of the invention include rigid, closed-cellpolyisocyanurate construction boards having an index of at least 290, adensity below 2.5 lbs/ft³, and include a pentane blowing agent (e.g.,acyclic pentane blowing agent) as defined herein. As the skilled personwill appreciate, R-Value can be determined according to ASTM C518-10.

INDUSTRIAL APPLICABILITY

In one or more embodiments, the construction boards of this inventionmay be employed in roofing or wall applications. In particularembodiments, the construction boards are used in flat or low-sloperoofing system.

In one or more embodiments, a roofing system may include a roof deckhaving an insulation board, which may be fabricated according topractice of this invention, disposed thereon. An optional high densityboard may be positioned above the insulation board relative to the roofdeck. A water-protective layer or membrane is disposed on top or abovehigh density board. In alternate embodiments, the high density board maybe positioned below the insulation board.

Practice of this invention is not limited by the selection of anyparticular roof deck. Accordingly, the roofing systems of this inventioncan include a variety of roof decks. Exemplary roof decks includeconcrete pads, steel decks, wood beams, and foamed concrete decks.

Practice of this invention is likewise not limited by the selection ofany water-protective layer or membrane. As is known in the art, severalmembranes can be employed to protect the roofing system fromenvironmental exposure, particularly environmental moisture in the formof rain or snow. Useful protective membranes include polymericmembranes. Useful polymeric membranes include both thermoplastic andthermoset materials. For example, and as is known in the art, membraneprepared from poly(ethylene-co-propylene-co-diene) terpolymer rubber orpoly(ethylene-co-propylene) copolymer rubber can be used. Roofingmembranes made from these materials are well known in the art asdescribed in U.S. Pat. Nos. 6,632,509, 6,615,892, 5,700,538, 5,703,154,5,804,661, 5,854,327, 5,093,206, and 5,468,550, which are incorporatedherein by reference. Other useful polymeric membranes include those madefrom various thermoplastic polymers or polymer composites. For example,thermoplastic olefin (i.e. TPO), thermoplastic vulcanizate (i.e. TPV),or polyvinylchloride (PVC) materials can be used. The use of thesematerials for roofing membranes is known in the art as described in U.S.Pat. Nos. 6,502,360, 6,743,864, 6,543,199, 5,725,711, 5,516,829,5,512,118, and 5,486,249, which are incorporated herein by reference. Inone or more embodiments, the membranes include those defined by ASTMD4637-03 and/or ASTM D6878-03.

Still in other embodiments, the protective membrane can includebituminous or asphalt membranes. In one embodiment, these asphaltmembranes derive from asphalt sheeting that is applied to the roof.These asphalt roofing membranes are known in the art as described inU.S. Pat. Nos. 6,579,921, 6,110,846, and 6,764,733, which areincorporated herein by reference. In other embodiments, the protectivemembrane can derive from the application of hot asphalt to the roof.

Other layers or elements of the roofing systems are not excluded by thepractice of this invention. For example, and as is known in the art,another layer of material can be applied on top of the protectivemembrane. Often these materials are applied to protect the protectivemembranes from exposure to electromagnetic radiation, particularly thatradiation in the form of UV light. In certain instances, ballastmaterial is applied over the protective membrane. In many instances,this ballast material simply includes aggregate in the form of rock,stone, or gravel; U.S. Pat. No. 6,487,830, is incorporated herein inthis regard.

The construction boards of this invention can be secured to a buildingstructure by using various known techniques. For example, in one or moreembodiments, the construction boards can be mechanically fastened to thebuilding structure (e.g., the roof deck). In other embodiments, theconstruction boards can be adhesively secured to the building structure.

In order to demonstrate the practice of the present invention, thefollowing examples have been prepared and tested. The examples shouldnot, however, be viewed as limiting the scope of the invention. Theclaims will serve to define the invention.

EXAMPLES

Samples 1-10

The following foam formulations were made and combined at laboratoryscale to produce foam samples that were then tested for variousproperties, as will be discussed in greater detail below. The foams wereprepared from two ingredient mixtures that included an A-side mixtureand a B-side mixture. The A-side mixture included a polymeric isocyanatebased upon diphenyl methane diisocyanate. The B-side mixture included100 parts by weight aromatic polyester polyol, about 10 parts by weightliquid flame retardant, about 3 parts by weight metal carboxylatecatalyst, about 0.3 parts by weight amine catalyst, about 2 parts byweight surfactant, about 0.25 parts by weight added water, and aphysical blowing agent blend that included isopentane, n-pentane, and anorganic compound (e.g. a blowing agent additive in accordance with thisinvention). The amount of the isopentane, the n-pentane, and theidentity and amount of the organic compound are provided in Table I. TheA-side mixture and the B-side mixture were combined in relative amountsto provide foam having an index of 287. The amount of physical blowingagent, together with the amount of water that was believed to beinherent within the ingredients and the amount of added water, weretailored to provide foams having a density of about 1.6 lbs/ft³.

TABLE I Samples 1 2 3 4 5 6 7 8 9 10 Blowing Agent Additive N/A HexaneMethyl Ethyl Methyl Chloroform Methylal Acetone Toluene Ethyl THF KetoneFormate Acetate Boiling Point (° C.) N/A 68 79.6 31.8 61.2 42 56 110.677 66 Hansen Factor (MPa^(−0.5)) N/A 14.9 19.0 18.7 19.0 17.5 20.0 18.218.1 19.4 R-Value (hr · ° F. · ft²/ Btu · in) 75° F. 6.492 6.062 6.5886.571 6.729 6.608 6.664 6.553 6.544 6.609 40° F. 5.626 5.417 7.032 6.9386.966 6.835 7.107 7.065 7.062 7.024 % Change −13 −11 +7 +6 +4 +3 +7 +8+8 +6

R-value was determined according to ASTM C518. Short-term dimensionalstability was determined according to ASTM D-2126-09 modified for usingsmaller sample size of 2″×2″×4″. Compression strength was determinedaccording to ASTM D-1621-10.

The data in Table I shows that the inclusion of certain organiccompounds having a solubility parameter greater than 17.0 MPa into thephysical blowing agent mixture improved the R-Value at a mediantemperature of 40° F. relative to the R-Value at a median temperature of75° F. over those foams where the physical blowing agent simply includedpentane (i.e. Sample 1). This result was highly unexpected. Furthermore,Table I shows that the inclusion of an organic compound not having therequisite solubility parameter (i.e. hexane of Sample 2) did not resultin an improvement in the R-Value at a median temperature of 40° F.relative to the R-Value at a median temperature of 75° F.

Samples 11-17

Using the foam forming technique and general formulation described abovefor Samples 1-10, additional foam samples were prepared using acetone asthe blowing agent additive at various levels. The amount of acetoneemployed in each sample, together with the amount of isopentane andn-pentane employed in each sample, is set forth in Table II togetherwith the initial R-value obtained at median temperatures of 75° F. and40° F. Table II also provides the percentage change in R-value betweenthese median temperatures. Table II also provides the compressivestrength measured in the rise direction (y direction) and a directionperpendicular to the rise direction (i.e. the x direction). Further,Table II provides the short-term dimensional stability represented as apercent change in volume.

TABLE II Samples 11 12 13 14 15 16 17 Physical Blowing Agent (php)Acetone 0 0.70 1.96 3.30 5.00 5.80 9.67 Isopentane 13.20 12.27 11.6611.77 10.29 9.13 6.60 N-Pentane 10.8 10.03 9.54 9.63 8.41 7.47 5.40Acetone (mole %) 0 4 10 16 25 30 50 Acetone (wt %) 0 3 8 13 21 26 45R-Value 75° F. 6.492 6.616 6.608 6.643 6.490 6.567 6.521 40° F. 5.6266.419 6.718 6.846 6.913 7.139 7.153 % Change −13 −3.0 1.7 3.1 6.5 8.79.7 Compressive Strength x-direction 32.3 37.0 35.4 42.6 29.6 32.5 24.1y-direction 13.4 15.1 14.0 11.3 11.5 10.6 7.66 Short-Term DimensionalStability % Volume Change −0.80 −0.79 −0.69 −0.47 — −0.74 −6.41

The data in Table II shows that the moles of blowing agent additiverelative to the moles of total physical blowing agent (i.e. the totalmoles of blowing agent additive and total moles of pentane) is criticalto achieving an improved R-Value at a median temperature of 40° F.relative to the R-Value at a median temperature of 75° F. The data inTable II also shows that limiting the amount of blowing agent additiverelative to the amount of total physical blowing agent is also criticalto maintaining adequate dimensional stability.

Samples 18-25

Using the foam forming technique and general formulation described abovefor Samples 11-17, additional foam samples were prepared using acetoneas the blowing agent together with isopentane, n-pentane, orcyclopentane, as shown in Table III. Table III also provides thepercentage change in R-value between the relevant median temperatures,as well as the compressive strength measured in the rise direction (ydirection) and a direction perpendicular to the rise direction (i.e. thex direction).

TABLE III Samples 18 19 20 21 22 23 24 25 Physical Blowing Agent (php)Acetone 3.30 3 2.9 2.9 5.00 4.8 4.8 4.8 Isopentane 11.77 20.3 10.29 18.0N-Pentane 9.63 20.4 8.41 18.0 Cyclopentane 20.4 18.0 Acetone (mole %) 1616 15 15 25 25 25 25 Acetone (wt %) 13.0 13.0 12.4 12.4 21.0 21.0 21.221.2 R-Value 75° F. 6.643 6.631 6.462 7.087 6.490 6.536 6.544 7.160 40°F. 6.846 6.979 6.928 7.057 6.913 7.118 6.945 7.407 % Change 3.1 5.2 7.2−0.4 6.5 8.9 6.1 3.4 Compressive Strength x-direction 42.6 31.7 28.731.3 23.6 29.3 30 30.9 y-direction 11.3 12 10.1 9.42 11.5 10.1 9.59 7.59

The data in Table III shows that the improvement in R-Value, derivingfrom the use of a blowing agent additive, at a 40° F. median temperaturerelative to the R-Value at a 75° F. median temperature is markedlygreater where the physical blowing agent is an acyclic pentane (i.e.isopentane or n-pentane) as compared to cyclopentane. These results wereunexpected.

Various modifications and alterations that do not depart from the scopeand spirit of this invention will become apparent to those skilled inthe art. This invention is not to be duly limited to the illustrativeembodiments set forth herein.

What is claimed is:
 1. A process for producing a polyurethane orpolyisocyanurate foam construction board, the process comprising: (i)providing an A-side reactant stream that includes a polymeric MDI; (ii)providing a B-side reactant stream that includes an aromatic polyesterpolyol, from about 1.0 to about 5.0 parts by weight surfactant, fromabout 5 to about 30 parts by weight of a flame retardant, up to 1.0parts by weight of added water, one or more catalysts to initiate thereaction between the polymeric MDI and the aromatic polyester polyol andto promote a trimerization reaction to form polyisocyanurate groups, andfrom about 12 to about 40 parts by weight of a physical blowing agentmixture that includes an acyclic pentane and acetone, where the amountsare based on 100 parts by weight of the aromatic polyester polyol, andwhere the physical blowing agent mixture includes from about 7 to about35 mole % of the acetone based on the total moles of physical blowingagent mixture; and (iii) mixing the A-side reactant stream with theB-side reactant stream to produce a reaction mixture, to thereby producea closed-cell foam having a density of from about 1.5 to about 1.8lbs/ft³, and an index of at least
 210. 2. The process of claim 1,further comprising exposing the reaction mixture to heat.
 3. The processof claim 2, where the reaction mixture is deposited onto a facer and thereaction mixture is processed within a laminator.
 4. The process ofclaim 1, where the process produces a construction board having an indexof at least
 220. 5. The process of claim 1, where the acyclic pentaneand the acetone form a physical blowing agent mixture, and where thephysical blowing agent mixture includes from about 10 to about 30 mole %of the acetone based on the total moles of physical blowing agentmixture.
 6. The process of claim 1, where the B-side reactant streamincludes less than 0.8 parts by weight water per 100 parts by weightpolyol.
 7. The process of claim 1, where the flame retardant is selectedfrom the group consisting of tri(monochloropropyl) phosphate andtri-2-chloroethyl phosphate.
 8. A process for producing a polyurethaneor polyisocyanurate construction board, the process comprising: (i)combining a polyester polyol, an isocyanate, an acyclic pentane blowingagent, acetone, and less than 0.6 parts by weight water per 100 parts byweight polyol to form a foam-forming mixture, where the ratio of polyolto isocyanate provides a closed-cell foam having an Index of at least210, and where the amount of acyclic pentane, acetone, and any waterpresent provide a closed-cell foam having a density of 1.0 to 2.5lbs/ft³, and where the acyclic pentane and acetone form a blowing agentmixture, and where the blowing agent mixture includes from about 7 toabout 35 mole % acetone based on the total moles of blowing agentmixture; (ii) depositing the foam-forming mixture on a facer; and (iii)heating the foam-forming mixture to form a closed-cell foam.